The Spatial Risk Multiplier Explained

Location, location, location are three important words for would-be property owners. But they're also crucial to developers aiming to reach the minimum 10% uplift in biodiversity net gain (BNG), a condition of planning law in England since 2024.¹

If the mitigation hierarchy's first principle of avoiding any impact on habitat can't be done, the biodiversity hierarchy then demands on-site enhancements are prioritised for BNG. For projects unable to meet that threshold, off-site biodiversity units are the next logical step.

However, they also open the door to the spatial risk multiplier. It is one of the most cost-sensitive aspects of BNG for developers seeking off-site solutions. It determines how many BNG units you actually need to buy and can significantly increase that number, depending on the location of the off-site habitat.

This guide explains what the spatial risk multiplier is and how it works in practice. We will examine the three tiers that determine your unit requirements, and what they mean for your BNG strategy and project costs.

What Is the Spatial Risk Multiplier?

The spatial risk multiplier is a mechanism that sits within the statutory biodiversity metric tool (the small sites metric does not have an off-site unit section, and so does not carry the multiplier).² It automatically adjusts the number of off-site BNG units a developer must buy, based on their proximity to the development site.

The point of biodiversity net gain is that it has a positive impact locally, so the further away the off-site habitat, the greater the risk that any ecological benefits will not be felt where the development took place.³

This is how the multiplier incentivises developers to find suitable units from habitat banks as close by as possible, rather than defaulting to lower-cost off-site units, regardless of location.

How Does the Spatial Risk Multiplier Work?

At the time of writing, the spatial risk multiplier reduced the biodiversity value of any off-site BNG units sourced outside a development's own local planning authority and National Character area boundaries.

In April 2026, the government confirmed this would change, and spatial risk would be based on local nature recovery strategy (LNRS) areas only.

Although there was no date given for the switch, the government said it would apply to all developments and would "increase flexibility for off-site BNG and better align with future local government reorganisation."⁴

Wherever they are applied, the multiplier acts in the same way.

It assigns a score based on geographic proximity, with three tiers determining how many biodiversity units actually count towards a development's required minimum 10% biodiversity net gain.⁵

Units Sourced Within the Same Local Planning Authority Area/Local Nature Recovery Strategy - No Penalty

Off-site biodiversity units from within the same LPA/LNRS carry no distance penalty and count at full face value towards a biodiversity gain plan.

If you can't meet your BNG obligations on-site, finding habitat banks within the same LPA or LNRS is the next best (and most cost-efficient) route to take.

Units Sourced from Neighbouring LPA/LNRS - 0.75 Multiplier

Any off-site BNG units sourced from a neighbouring LPA or LNRS - one that shares a boundary with your development site's LPA or LNRS - a 0.75 penalty will be applied.

That means for every single unit needed, a developer must buy 1.33 units to account for the increased spatial risk.

Units from Outside Neighbouring LPA/LNRS Areas - 0.5 Multiplier

Outside a neighbouring LPAs or LNRS, a 0.5 penalty applies, halving the value of a single unit.

The biodiversity metric will demand twice as many units to compensate for the distance in habitat creation, compared to the location of the development.

The Spatial Risk Multiplier and Statutory Biodiversity Credits

The spatial risk multiplier has a particularly harsh sting when it comes to statutory biodiversity credits.

These last-resort BNG solutions⁶ are bought from the UK government where all efforts to find suitable on- or off-site enhancements to meet the minimum 10% uplift have failed.

Statutory biodiversity credits are deliberately priced very high⁷ as a deterrent to developers looking to sidestep the biodiversity hierarchy.

However, because they are not linked to any specific local planning authority, the full 0.5 penalty applies, so developers must buy twice the amount they need, maximising the financial cost.

The trading rules within the statutory biodiversity metric and the small sites metric tools prevent developers from swapping low-value spaces for high-value lost habitat, regardless of where off-site units are sourced.

Meeting both the trading rules and the spatial risk requirements should be planned for together.

How the Spatial Risk Multiplier Affects Your BNG Strategy

Understanding how the spatial risk multiplier could affect a project as early as possible in the design process is essential to both a sound BNG strategy and timely cost planning.

Finding out the number of units needed is higher than expected only when their ecological consultant runs the biodiversity metric tool's calculation can be too late for some projects, potentially putting their viability at risk.

Prioritise On-Site Delivery

The spatial risk multiplier is a good reason why maximising on-site delivery before turning to off-site solutions makes solid financial sense.

Every additional biodiversity unit a developer can credibly deliver within the red line boundary of a project is a unit that does not need to be sourced off-site, avoiding any penalty.

For developments where significant on-site habitat creation is feasible and practical, it's the most cost-effective route to meeting the minimum 10% BNG requirement.

Source Off-Site Biodiversity Units Locally

In situations where relying on off-site BNG solutions is unavoidable, the spatial risk multiplier acts as a robust incentive for developers to source units as close to their project site as possible.

Working with an experienced habitat bank provider - like us - who operates nationally means developers can quickly identify if suitable units are available close to their site, rather than defaulting to those further away simply because they were the first to be found.

Model the Spatial Risk Early

At every stage in the planning and biodiversity net gain processes, taking action as early as possible is always beneficial.

Examining the mitigation hierarchy to avoid or minimise the ecological impact of a project can save developers time and money.

For projects that trigger BNG, experienced ecologists can model various off-site scenarios, detailing cost and availability when sourcing BNG units that are closer to 'home', instead of further afield.

All these informed decisions are best made before committing to a habitat bank, rather than after submitting a biodiversity gain plan.

We Can Help You Find the Right BNG Solutions

If you need help understanding if the spatial risk penalty applies to your development site, or want to find off-site BNG units within your LPA/LNRS, talk to us.

We operate habitat banks across England and can quickly confirm what is available in the most cost-efficient spatial risk tier for your project.

Email us at sales@greenshank-environmental.com or fill in this contact form and we'll be in touch as soon as possible.

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